1. Field of the Invention
The present invention relates generally to a satellite communications or broadcasting system and a satellite signal receiving terminal for supplying a variety of lifestyle information by means of a satellite communications or broadcasting channel.
2. Description of the Prior Art
The following description takes as its example a bi-directional shopping system using a CATV cable channel and a telephone channel.
FIG. 36 is a block diagram of an example of an Interactive Multimedia Presentation and Communications System disclosed in U.S. Pat. No. 5,191,410. 60 is a home, 61 is a television which receives and displays an analog television signal, 62 is a control pad of a touch-tone telephone, and the user connects to a local operating center (hereinafter abbreviated to LOC) by dialling an LOC telephone number displayed on the television screen. The user then transmits a number corresponding to the desired shopping information or comments relating to that information displayed on the television screen via a telephone line 66 to LOC 63. LOC 63 allocates an identifier which identifies the user (the user's receiving terminal) corresponding to that telephone number and together with the shopping information which has been requested sends information to the head end of the CATV to which the user is subscribing.
FIG. 37 shows an example of a frame configuration of the multi-layered shopping information when this address has been allocated. S is a frame synchronizing signal; Da, Db, Dc are data of the shopping information (hereinafter referred to as "data"); Pa, Pb, Pc are identifiers of user receiving terminals 60A, 60B, 60C; 5 is a header to which a receiving terminal identifier is inserted; a packet is comprised of a header 5 and data, and one frame is comprised of a frame synchronizing signal and a multi-layered plurality of packets. A head end 64 of the CATV carries out digital modulation of this frame with a frequency band determined beforehand and transmits it on a CATV cable 67. A presentation player 65 contains a plurality of players synchronized with a plurality of receiving terminals in order to carry out this data service, and a number of receiving terminals greater than this simultaneous processing ability is apportioned to one presentation player. From these, the presentation player picks out only the data which have a receiving terminal identifier for which the presentation player itself is responsible, converts these data to an analog television signal, and transmits the television signal of the requested shopping information on a special-purpose channel apportioned beforehand into receiving terminals 60A, 60B, and 60C. The analog television programs now flowing from the CATV head end are now transmitted unchanged on other channels to each of the receiving terminals.
In general, shopping information is concentrated on a single piece of information, and in a case in which the receiving terminals 60A, 60B, and 60C have simultaneously or almost simultaneously requested identical data, for instance Da, the frame configuration becomes that shown in FIG. 38 and the same Da data are multiply transmitted to each of the packets. In such a case, the receiving terminal identifiers of each of the receiving terminals 60A, 60B, and 60C are distributed in advance by some means.
Since previous shopping systems using a CATV cable channel have been configured as described above, a multitude of identical data having different destinations have existed within the same frame with the resulting problems that the channels become occupied and the transmission efficiency of the shopping data decreases.
Furthermore, in the case of advertisements, commercials, and shopping malls and the like capable of virtual shopping, although common information is available to the user, since each of the receiving terminals make requests to the information center separately this leads to the problems that processing of the local operation center becomes extremely complex, accessing takes a long time, and the transmission efficiency of the shopping data decreases.
Moreover, even in a case in which shopping information is displayed as a stationary image, since this is converted to an analog signal at the presentation player and transmitted to each of the receiving terminals, the preparation of special channels capable of simultaneously accessing this shopping data service requires a considerable number of MHz, for instance the preparation of 8 channels (i.e. 8 receiving terminals) for one presentation player uses 48 MHz, thus this band cannot be used so as to reach a user belonging to this presentation player not using the service, causing great problems for the service.